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About data pipelines</TITLE>
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<A NAME="X-REF304004393"></A><h1>About data pipelines</h1>
<A NAME="TI2795"></A><p>PowerBuilder provides a feature called the <strong>data
pipeline</strong> that you can use to migrate data between database
tables. This feature makes it possible to copy rows from one or
more source tables to a new or existing destination table&#8212;either
within a database, or across databases, or even across DBMSs.</p>
<A NAME="TI2796"></A><h4>Two ways to use data pipelines</h4>
<A NAME="TI2797"></A><p>You can take advantage of data pipelines in two different
ways:<A NAME="TI2798"></A>
<ul>
<li class=fi><b>As a utility
service for developers</b>   <br>
While working in the PowerBuilder development environment,
you might occasionally want to migrate data for logistical reasons
(such as to create a small test table from a large production table).
In this case, you can use the Data Pipeline painter interactively
to perform the migration immediately.<br><br>
For more information on using the Data Pipeline
painter this way, see the PowerBuilder <i>Users Guide</i>
.<br></li>
<li class=ds><b>To implement data migration capabilities
in an application</b>   <br>
If you are building an application whose requirements call
for migrating data between tables, you can design an appropriate
data pipeline in the Data Pipeline painter, save it, and then enable
users to execute it from within the application.<br><br>
This technique can be useful in many different situations,
such as: when you want the application to download local copies
of tables from a database server to a remote user, or when you want
it to roll up data from individual transaction tables to a master
transaction table.<br>
</li>
</ul>
</p>
<A NAME="TI2799"></A><h4>Walking through the basic steps</h4>
<A NAME="TI2800"></A><p>If you determine that you need to use a data pipeline in your
application, you must determine what steps this involves. At the
most general level, there are five basic steps that you typically
have to perform.</p>
<A NAME="TI2801"></A><p><img src="images/proc.gif" width=17 height=17 border=0 align="bottom" alt="Steps"> To pipe data in an application:</p>
<ol><li class=fi><p>Build the objects you need.</p></li>
<li class=ds><p>Perform some initial housekeeping.</p></li>
<li class=ds><p>Start the pipeline.</p></li>
<li class=ds><p>Handle row errors.</p></li>
<li class=ds><p>Perform some final housekeeping.</p></li></ol>
<br><A NAME="TI2802"></A><p>The remainder of this chapter gives you the details of each
step.</p>

